I finally got around to pulling off the right side crankcase cover to see why the clutch was slipping at high revs.
I managed to remove the cover without disassembling the oil pump and those very delicate 52 y/o fine threads. They are well known to need helicoiled at the drop of a hat. I had a new gasket for under the oil pump body. The oil pump cable removal was the biggest faff,not much room in there to get at the cable adjusting screw.
Kawasaki H1B - Imgur (14).jpg (3.31 MiB) Viewed 203 times
The minimum service limit for the clutch springs is 34mm,some were a little over that,but most were under. I replaced the worst with 3 ebc heavy duty springs. I didn't do them all,because the pull at the lever was noticeably heavier with 3 springs and I didn't want it any heavier,if I can get away with no clutch slip at that.
Kawasaki H1B - Imgur (13).jpg (2.17 MiB) Viewed 203 times
Attachments
Kawasaki H1B - Imgur (12).jpg (2.05 MiB) Viewed 203 times
Last edited by Skub on Thu Oct 02, 2025 8:24 pm, edited 1 time in total.
That's one hell of an oil pump you have there... Proper chunky unit. I'm having similar issues with heavy clutch action, but have decided not to go with the 15% heavier EBC springs that came with the clutch pack, but instead go with new OE springs. I'll be interested to see how you get on with the mix and match approach. It's a familar ploy on the LC forum - people use 3 x OE and 3 x EBC.
What gets me is why these old bikes have such a (comparatively) heavy clutch action for their modest (by today's standards) power output. My 72bhp KTM Duke has an absolute feather light clutch action, whereas the clutch of my 42bhp LC is a fair bit heavier than I'm comfortable with.
Liking the posh Mitutoyo vernier calipers - very snazzy...
mangocrazy wrote: Mon Dec 30, 2024 6:58 pm
What gets me is why these old bikes have such a (comparatively) heavy clutch action for their modest (by today's standards) power output.
One (sort of) reason is people didn’t think that was a heavy clutch, because their comparison was men’s bikes (shitheaps) like the Norton Atlas or BSA A65.
mangocrazy wrote: Mon Dec 30, 2024 6:58 pm
What gets me is why these old bikes have such a (comparatively) heavy clutch action for their modest (by today's standards) power output. My 72bhp KTM Duke has an absolute feather light clutch action, whereas the clutch of my 42bhp LC is a fair bit heavier than I'm comfortable with.
It may have something to do with the action and possibly the age of the clutch actuator. There's a German chap (Ralf Gille) who makes one for triples and it gives a much lighter feel to most bikes.
Yes, progress comes in a variety of forms and comparisons across generations aren't always a good idea. You've only got to look at the suspension and brakes of 70s/80s bikes compared to modern bikes. Why should clutches be any different?
Test run today and although the lever action is heavier,I'm happy to report no clutch slip. I need a less slippery seat for when it hits 7k now. Properly caught me out.
Skub wrote: Tue Dec 31, 2024 3:12 pm
Test run today and although the lever action is heavier,I'm happy to report no clutch slip. I need a less slippery seat for when it hits 7k now. Properly caught me out.
Being serious, does it still give you a buzz?
Not gonna be like the big Z but might still go a bit.
Yorick wrote: Tue Dec 31, 2024 4:18 pm
Being serious, does it still give you a buzz?
Not gonna be like the big Z but might still go a bit.
Yeah,both 500s are highly entertaining to ride. Anyone expecting modern performance in any area is going to be disappointed,a modern bike will piss all over them in all departments,but riding them for what they are puts a smile on my face every time.
The two were very light in action and similar. The H1a clutch has never slipped,so I'm not fixing what isn't broken.
It's the same clutch on both models,as far as I recall,so maybe they all sail close to the wind and out of spec springs are the tipping point. Probably the first course of action and the most sensible would have been to fit new 'in spec' stock springs,that way the feel stays light and the clutch doesn't slip. Maybe!
I think they're pretty much on the limit, even with new plates. I had SS50 valve springs in mine for racing. Too heavy for the road but OK when you only ever use the clutch for down changes.
I fitted some lower bars to Mr.Orange today. The Murcan spec bars were too high for my taste and not very comfy either. Maybe help a little with the wayward handling at speed too. Hopefully.
20250425_145031.jpg (3.7 MiB) Viewed 202 times
Last edited by Skub on Thu Oct 02, 2025 8:27 pm, edited 1 time in total.
Druid wrote: Fri Apr 25, 2025 7:03 pm
Good move, they look much better. But I think it will take a bit more than a set of bars to fix the handling on a Kawasaki triple
Ha! Very likely.
It's strange though,the B is everything you'd expect of a 70s Kawasaki triple,yet the H1A handles very well,considering. It's the limitations of no brakes and ground clearance,but no normal death weaves on the A. The B over 70 is er...interesting and requires full attention.
Those Merkin spec high bars are a bad idea. They turn the rider into an involuntary sail, so you're unwittingly pulling on the bars and making the front end light. So good move with the lower bars. Hope it makes Mr Orange a little less flappy.
).
